TECHNICAL FIELD
[0001] The present invention relates to a fluorinated imide salt compound and a surfactant.
BACKGROUND ART
[0003] Fluorinated compounds having a perfluoroalkyl group are widely used as fluorine-based
surfactants because these compounds have excellent surface activity. As the fluorine-based
surfactants, perfluorooctanoic acid (PFOA) and perfluorooctanesulfonic acid (PFOS)
are known. In recent years, it has been revealed that compounds containing a linear
perfluoroalkyl group having 7 or more carbon atoms are highly toxic and highly bioaccumulative.
Therefore, the use of PFOA or PFOS has been restricted. Accordingly, surfactants as
alternative materials for PFOA and PFOS have been in development.
[0004] Patent Literature 1 discloses ammonium bis(perfluorobutanesulfonyl)imide: NH
4+-N(SO
2C
4F
9)
2. According to Patent Literature 1, the ammonium bis(perfluorobutanesulfonyl)imide
is more able to reduce surface tension than the ammonium salt of perfluorooctanoic
acid (PFOA).
[0005] In Patent Literature 2, as a surfactant to be added to a lithography composition
used for manufacturing a semiconductor integrated circuit, a flat panel display (FPD),
a circuit board, a color filter, and the like, a fluorinated imide compound containing
a fluorocarbon group having 5 or less carbon atoms is disclosed.
[0006] Patent Literature 3 discloses fluoroalkyl-containing imides and salts thereof for
use as surfactants.
[Citation List]
[Patent Literature]
SUMMARY OF INVENTION
Technical Problem
[0008] Ammonium bis(perfluorobutanesulfonyl)imide disclosed in Patent Literature 1 is more
able to reduce surface tension than PFOA. However, according to the study conducted
by the inventors of the present invention, the surface tension-reducing ability of
the ammonium bis(perfluorobutanesulfonyl)imide is lower than that of PFOS, and needs
to be further improved. Furthermore, the fluorinated imide compound disclosed in Patent
Literature 2 tends to be easily hydrolyzed in water and to exhibit low stability in
water.
[0009] The present invention has been made in consideration of the above circumstances,
and an object thereof is to provide a novel compound and a surfactant that do not
contain a linear perfluoroalkyl group having 7 or more carbon atoms, has a high surface
tension-reducing ability, and exhibit excellent stability in water.
Solution to Problem
[0010] A compound of the present invention for achieving the above object is a fluorinated
imide salt compound represented by General Formula (1).

[0011] In General Formula (1), m represents 1 or 2, n represents an integer from 1 to 4,
α represents 1 or 2, and X
α+ represents an α-valent metal ion, a primary ammonium ion, a secondary ammonium ion,
a tertiary ammonium ion, a quaternary ammonium ion, or NH
4+.
[0012] The fluorinated imide salt compound of the present invention contains a metal ion,
a primary ammonium ion, a secondary ammonium ion, a tertiary ammonium ion, a quaternary
ammonium ion, or NH
4+, and has an imide structure having high ion dissociation properties. Therefore, this
compound is highly hydrophilic. Furthermore, this compound has a salt structure. Therefore,
the compound is more stable in water and can be easily used for various uses. In addition,
the compound has a structure in which an oxyperfluoropropyl group: [CF
3-CF
2-CF
2-O-] is bonded to a carboxylic acid group of imide through an oxyperfluoropropylene
group: [-CF(CF
3)-CF
2-O-], and a perfluoroalkyl group having 4 or less carbon atoms is directly bonded
to a sulfonic acid group of imide. Therefore, the compound is highly hydrophobic and
highly lipophobic. Accordingly, the fluorinated imide salt compound of the present
invention has high solubility in an aqueous solvent or an organic solvent, exhibits
excellent stability in water, and has a high surface tension-reducing ability.
[0013] The compound of the present invention may be a fluorinated imide salt compound represented
by General Formula (2).

[0014] In General Formula (2), m represents 1 or 2, n represents an integer from 1 to 4,
α represents 1 or 2, and M
α+ represents an α-valent metal ion, a primary ammonium ion, a secondary ammonium ion,
a tertiary ammonium ion, or a quaternary ammonium ion.
[0015] The fluorinated imide salt compound of the present invention contains a metal ion,
a primary ammonium ion, a secondary ammonium ion, a tertiary ammonium ion, or a quaternary
ammonium ion, and has an imide structure having high ion dissociation properties.
Therefore, this compound is highly hydrophilic. Furthermore, this compound has a salt
structure. Therefore, the compound is more stable in water and can be easily used
for various uses. In addition, the compound has a structure in which an oxyperfluoropropyl
group: [CF
3-CF
2-CF
2-O-] is bonded to a carboxylic acid group of imide through an oxyperfluoropropylene
group: [-CF(CF
3)-CF
2-O-], and a perfluoroalkyl group having 4 or less carbon atoms is directly bonded
to a sulfonic acid group of imide. Therefore, the compound is highly hydrophobic and
highly lipophobic. Accordingly, the fluorinated imide salt compound of the present
invention has high solubility in an aqueous solvent or an organic solvent, exhibits
excellent stability in water, and has a high surface tension-reducing ability.
[0016] The compound of the present invention may be a fluorinated imide salt compound represented
by General Formula (3).

[0017] In General Formula (3), m represents 1 or 2, and n represents an integer from 1 to
4.
[0018] The fluorinated imide salt compound of the present invention contains an ammonium
ion and has an imide structure having high ion dissociation properties. Therefore,
this compound is highly hydrophilic. Furthermore, this compound has an ammonium salt
structure. Therefore, this compound is more stable in water and can be easily used
for various uses. This compound is highly hydrophilic and exhibits high stability
in water. In addition, the compound has a structure in which an oxyperfluoropropyl
group is bonded to a carboxylic acid group of imide through an oxyperfluoropropylene
group, and a perfluoroalkyl group having 4 or less carbon atoms is directly bonded
to a sulfonic acid group of imide. Therefore, the compound is highly hydrophobic and
highly lipophobic. Accordingly, the fluorinated imide salt compound of the present
invention has high solubility in an aqueous solvent or an organic solvent, exhibits
excellent stability in water, and has a high surface tension-reducing ability.
[0019] A surfactant of the present invention contains the fluorinated imide salt compound
described above.
[0020] Because the surfactant of the present invention contains the fluorinated imide salt
compound described above, the surfactant has a high surface tension-reducing ability.
ADVANTAGEOUS EFFECTS OF INVENTION
[0021] According to the present invention, it is possible to provide a novel compound and
a surfactant that do not contain a linear perfluoroalkyl group having 7 or more carbon
atoms, have a high surface tension-reducing ability, and exhibit excellent stability
in water.
DESCRIPTION OF EMBODIMENTS
[0022] Hereinafter, the fluorinated imide salt compound and the surfactant according to
embodiments of the present invention will be described.
<Fluorinated imide salt compound>
[0023] The fluorinated imide salt compound according to an embodiment of the present invention
is a compound represented by General Formula (1).

[0024] In General Formula (1), m represents 1 or 2, n represents an integer from 1 to 4,
α represents 1 or 2, and X
α+ represents an α-valent metal ion, a primary ammonium ion, a secondary ammonium ion,
a tertiary ammonium ion, a quaternary ammonium ion, or NH
4+.
[0025] According to a first embodiment of the present invention, the fluorinated imide salt
compound represented by General Formula (1) is a compound in which α represents 1
or 2, and X
α+ represents an α-valent metal ion, a primary ammonium ion, a secondary ammonium ion,
a tertiary ammonium ion, or a quaternary ammonium ion. According to a second embodiment
of the present invention, the fluorinated imide salt compound represented by General
Formula (1) is a compound in which α represents 1, and X
α+ represents NH
4+. Hereinafter, the first embodiment and the second embodiment will be described.
[First embodiment]
[0026] The fluorinated imide salt compound according to the first embodiment of the present
invention is a compound represented by General Formula (2).

[0027] In General Formula (2), m represents 1 or 2, n represents an integer from 1 to 4,
α represents 1 or 2, and M
α+ represents an α-valent metal ion, a primary ammonium ion, a secondary ammonium ion,
a tertiary ammonium ion, or a quaternary ammonium ion.
[0028] The fluorinated imide salt compound represented by General Formula (2) has a structure
in which m represents 1 or 2, and an oxyperfluoropropyl group is bonded to a carboxylic
acid group of imide through an oxy perfluoropropylene group. Therefore, this compound
has higher hydrophobicity and higher lipophobicity. In a case where m is 0, the hydrophobicity
and lipophobicity are reduced, and the surface tension-reducing ability is lowered.
Meanwhile, because the compound in which m is 3 or greater is difficult to synthesize,
the synthesis cost increases.
[0029] The fluorinated imide salt compound of represented by General Formula (2) has a structure
in which n is an integer from 1 to 4, and a perfluoroalkyl group having 4 or less
carbon atoms is directly bonded to a sulfonic acid group of imide. Therefore, this
compound has higher hydrophobicity and higher lipophobicity.
[0030] The fluorinated imide salt compound represented by General Formula (2) has a fluorocarbon
group (an oxyperfluoropropylene group, an oxyperfluoropropyl group, or a perfluoroalkyl
group) having a carbon chain consisting of 4 or less carbon atoms. This compound is
preferable because such a compound is rapidly excreted from a living body and less
bioaccumulative. Generally, the shorter the carbon chain of the fluorocarbon group
is in a fluorinated compound, the lower the surface activity of the compound tends
to be. The fluorinated imide salt compound of the present embodiment has the structure
described above. Therefore, the compound has high surface activity even though the
carbon chain of each fluorocarbon group consists of 4 or less carbon atoms.
[0031] The fluorinated imide salt compound represented by General Formula (2) has a structure
in which M
α+ represents an α-valent metal ion, a primary ammonium ion, a secondary ammonium ion,
a tertiary ammonium ion, or a quaternary ammonium ion. Therefore, the compound exhibits
high ion dissociation properties in water. Accordingly, the compound is highly hydrophilic.
In addition, because the compound has a salt structure, the compound is more stable
in water.
[0032] Examples of the monovalent metal ion include a lithium ion, a sodium ion, and a potassium
ion. Examples of the divalent cation include a magnesium ion and a calcium ion.
[0033] The primary ammonium ion preferably has an alkyl group having 1 to 10 carbon atoms
or an aralkyl group having 6 to 10 carbon atoms. Examples of the primary ammonium
ion include a methylammonium ion, an ethylammonium ion, a 1-propylammonium ion, a
2-propylammonium ion, a n-butylammonium ion, a 2-butylammonium ion, and a benzylammonium
ion.
[0034] The secondary ammonium ion preferably has an alkyl group having 1 to 10 carbon atoms
or an aralkyl group having 7 to 10 carbon atoms. In a case where the secondary ammonium
ion has 2 alkyl groups, the 2 alkyl groups may be linked to each other to form a ring
structure. The ring structure may contain an oxygen atom, a sulfur atom, a ketone
group, an ester bond, or an amide bond. Examples of the secondary ammonium ion include
a dimethylammonium ion, a diethylammonium ion, a di-1-propylammonium ion, a di-2-propylammonium
ion, a di-n-butylammonium ion, a di-2-butylammonium ion, a dibenzylammonium ion, a
benzylmethylammonium ion, a benzylethylammonium ion, a benzylpropylammonium ion, a
benzylbutylammonium ion, an ethylmethylammonium ion, a methylpropylammonium ion, an
ethylpropylammonium ion, a methylbutylammonium ion, an ethylbutylammonium ion, a propylbutylammonium
ion, a pyrrolidinium ion, a piperidinium ion, and a morpholinium ion.
[0035] The tertiary ammonium ion preferably has an alkyl group having 1 to 10 carbon atoms
or an aralkyl group having 7 to 10 carbon atoms. In a case where the tertiary ammonium
ion has 2 or more alkyl groups, the 2 alkyl groups may be linked to each other to
form a ring structure. The ring structure may contain an oxygen atom, a sulfur atom,
a ketone group, an ester bond, or an amide bond. Examples of the tertiary ammonium
ion include a trimethylammonium ion, a triethylammonium ion, a tri-1-propylammonium
ion, a tri-2-propylammonium ion, a tri-n-butylammonium ion, a tri-2-butylammonium
ion, a tribenzylammonium ion, a dibenzylmethylammonium ion, a dibenzylethylammonium
ion, a dibenzylpropylammonium ion, a dimethylethylammonium ion, a dimethylpropylammonium
ion, a dimethylbutylammonium ion, a diethylmethylammonium ion, a diethylpropylammonium
ion, a diethylbutylammonium ion, a dipropylmethylammonium ion, a dipropylethylammonium
ion, a dipropylbutylammonium ion, a dibutylmethylammonium ion, a dibutylethylammonium
ion, a dibutylpropylammonium ion, a methylpyrrolidinium ion, an ethylpyrrolidinium
ion, a methylpiperidinium ion, an ethylpiperidinium ion, a methylmorpholinium ion,
and an ethylmorpholinium ion.
[0036] The quaternary ammonium ion preferably has an alkyl group having 1 to 10 carbon atoms
or an aralkyl group having 7 to 10 carbon atoms. In a case where the tertiary ammonium
ion has 2 or more alkyl groups, the 2 alkyl groups may be linked to each other to
form a ring structure. The ring structure may contain an oxygen atom, a sulfur atom,
a ketone group, an ester bond, or an amide bond. Examples of the quaternary ammonium
ion include a tetramethylammonium ion, a tetraethylammonium ion, a tetra(1-propyl)ammonium
ion, a tetra(2-propyl)ammonium ion, a tribenzylmethylammonium ion, a tribenzylethylammonium
ion, a tribenzylpropylammonium ion, a tribenzylbutylammonium ion, a dibenzylethylmethylammonium
ion, a tetra(n-butyl)ammonium ion, a tetra(2-butyl)ammonium ion, a dimethylpyrrolidinium
ion, a diethylpyrrolidinium ion, an ethylmethylpyrrolidinium ion, a dimethylpiperidinium
ion, a diethylpiperidinium ion, an ethylmethylpiperidinium ion, a dimethylmorpholinium
ion, a diethylmorpholinium ion, and an ethylmethylmorpholinium ion.
[0037] Next, a method for manufacturing the fluorinated imide salt compound of the present
embodiment will be described. A fluorinated imide metal salt compound containing an
α-valent metal ion as M
α+ can be manufactured, for example, by a method in which a reaction is caused between
carbonyl fluoride: CF
3-CF
2-CF
2-O-[CF(CF
3)-CF
2-O]
m-CF(CF
3)-COF and a metal salt of a perfluoroalkylsulfonamide compound: [CnF
2n+1-SO
2NH]
αM
α+ in the presence of a fluoride: M
1F and a solvent as illustrated in Reaction Formula (A).

[0038] In Reaction Formula (A), m, n, and α have the same definitions as m, n, and α in
General Formula (2). M
1 represents a monovalent cation. Examples of the monovalent cation include a hydrogen
ion, a lithium ion, a sodium ion, a potassium ion, an ammonium ion, a primary ammonium
ion, a secondary ammonium ion, a tertiary ammonium ion, and a quaternary ammonium
ion.
[0039] Carbonyl fluoride: CF
3-CF
2-CF
2-O-[CF(CF
3)-CF
2-O]
m-CF(CF
3)-COF is a derivative of hexafluoropropylene oxide (HFPO). As this compound, commercially
available products can be used. For example, as CF
3CF
2CF
2OCF(CF
3)CF
2OCF(CF
3)COF, it is possible to use CHEMINOX PO-3-AF marketed by Unimatec Corporation.
[0040] The metal salt of the perfluoroalkyl sulfonamide compound: [C
nF
2n+1-SO
2NH]
αM
α can be manufactured, for example, by a method including a first step of causing a
reaction between perfluoroalkyl sulfonyl fluoride (C
nF
2n+1-SO
2F) and ammonia so as to obtain a reaction solution containing an ammonium salt of
perfluoroalkyl sulfonamide (C
nF
2n+1-SO
2NH NH
4) and ammonium fluoride (NH
4F) and a second step of causing a reaction between the reaction solution and a metal
compound. As the metal compound, for example, it is possible to use at least one kind
of compound selected from hydroxides, carbonates, and bicarbonates of monovalent metals
(lithium, sodium, and potassium) or divalent metals (magnesium and calcium). The first
step and the second step can be performed, for example, by using the method described
in
Japanese Patent No. 5730513.
[0041] The fluoride: M
1F has an action of capturing hydrofluoric acid generated by the reaction between carbonyl
fluoride and the metal salt of the perfluoroalkyl sulfonamide compound.
[0042] As the solvent, an organic solvent can be used. The organic solvent is not particularly
limited as long as it does not inhibit the above reaction. For example, ethyl acetate
and acetonitrile can be used.
[0043] The reaction illustrated in Reaction Formula (A) can be carried out, for example,
by mixing carbonyl fluoride with the metal salt of the perfluoroalkyl sulfonamide
compound in the presence of a fluoride and a solvent and stirring the mixture. As
a method of mixing the carbonyl fluoride with the metal salt of the perfluoroalkyl
sulfonamide compound, it is possible to use a method of adding dropwise the carbonyl
fluoride to the mixed solution containing the metal salt of the perfluoroalkyl sulfonamide
compound, the fluoride, and the solvent.
[0044] The reaction temperature is not particularly limited, but is preferably 70°C or lower,
and particularly preferably in a range of 0°C to 40°C.
[0045] After the reaction ends, the fluorinated imide metal salt compound generated in the
reaction solution can be isolated and purified by known methods such as extraction,
filtration, and concentration.
[0046] The fluorinated imide salt compound containing a primary ammonium ion, a secondary
ammonium ion, a tertiary ammonium ion, or a quaternary ammonium ion as M
α+ can be manufactured as follows, for example.
[0047] First, the fluorinated imide metal salt compound containing an α-valent metal ion
as M
α+ is acidolyzed using sulfuric acid or hydrochloric acid, thereby obtaining a fluorinated
imide compound containing a hydrogen atom as M
α+. Then, the obtained fluorinated imide compound is neutralized with an amine compound
that generates a primary ammonium ion, a secondary ammonium ion, a tertiary ammonium
ion, or a quaternary ammonium ion.
[0049] The fluorinated imide salt compound of the present embodiment contains a metal ion,
a primary ammonium ion, a secondary ammonium ion, a tertiary ammonium ion, or a quaternary
ammonium ion, and has an imide structure having high ion dissociation properties.
Accordingly, the compound is highly hydrophilic. In addition, because the compound
has a salt structure, the compound is more stable in water. In addition, the compound
has a structure in which an oxyperfluoropropyl group: [CF
3-CF
2-CF
2-O-] is bonded to a carboxylic acid group of imide through an oxyperfluoropropylene
group: [-CF(CF
3)-CF
2-O-], and a perfluoroalkyl group having 4 or less carbon atoms is directly bonded
to a sulfonic acid group of imide. Therefore, the compound is highly hydrophobic and
highly lipophobic. Accordingly, the fluorinated imide salt compound of the present
embodiment has high solubility in an aqueous solvent or an organic solvent, exhibits
excellent stability in water, and has a high surface tension-reducing ability.
[Second Embodiment]
[0050] The fluorinated imide salt compound according to the second embodiment of the present
invention is a compound represented by General Formula (3).

[0051] in General Formula (3), m represents 1 or 2, and n represents an integer from 1 to
4.
[0052] The structure of the fluorinated imide salt compound of the present embodiment is
the same as the structure of the fluorinated imide salt compound of the first embodiment,
except that the fluorinated imide salt compound of the first embodiment is a fluorinated
imide ammonium salt compound in which α represents 1 and M
α+ represents an ammonium ion.
[0053] The fluorinated imide ammonium salt compound of the present embodiment can be manufactured,
for example, by acidolyzing a fluorinated imide metal salt compound containing an
α-valent metal ion as M
α+ by using sulfuric acid or hydrochloric acid so as to obtain a fluorinated imide compound
containing a hydrogen atom as M
α+, and then neutralizing the obtained fluorinated imide compound with ammonia.
[0054] The fluorinated imide ammonium salt compound of the present embodiment contains an
ammonium ion and has an imide structure having high ion dissociation properties. Therefore,
this compound is highly hydrophilic and highly stable in water. In addition, the compound
has a structure in which an oxyperfluoropropyl group is bonded to a carboxylic acid
group of imide through an oxyperfluoropropylene group, and a perfluoroalkyl group
having 4 or less carbon atoms is directly bonded to a sulfonic acid group of imide.
Therefore, the compound is highly hydrophobic and highly lipophobic. Accordingly,
the fluorinated imide ammonium salt compound of the present embodiment has high solubility
in an aqueous solvent or an organic solvent, exhibits excellent stability in water,
and has a high surface tension-reducing ability.
<Surfactant>
[0055] The surfactant of the present embodiment contains the fluorinated imide salt compound
described above. One kind of fluorinated imide salt compound may be used singly, or
2 or more kinds of fluorinated imide salt compounds may be used in combination. The
surfactant of the present embodiment may contain a compound other than the fluorinated
imide salt compound described above.
[0056] The surfactant of the present embodiment is easily dissolved in various products
using aqueous solvents or organic solvents, for example, various coating materials
or molding materials such as printing materials, photosensitive materials, photographic
materials, paint, cleaning agents, optical materials, and release agents. Therefore,
in these materials, the surfactant can be suitably used as an additive for enhancing
permeability/wettability, leveling properties, surface functionality, and the like.
[0057] Particularly, the fluorinated imide salt compound of the first embodiment that contains
a primary ammonium ion, a secondary ammonium ion, a tertiary ammonium ion, or a quaternary
ammonium ion as M
α+ and the fluorinated imide ammonium salt compound of the second embodiment do not
contain a metal. Therefore, surfactants containing these fluorinated imide salt compounds
can be advantageously used in a semiconductor manufacturing process or used as coating
additives or surface treatment agents for electronic parts.
[0058] The organic solvent for dissolving the surfactant of the present embodiment is not
particularly limited. Examples of the organic solvent include an alcohol such as methanol
or ethanol, an ester-based solvent such as ethyl acetate, a ketone-based solvent such
as acetone or N-methyl-2-pyrrolidone (NMP), an ether-based solvent such as propylene
glycol monomethyl ether acetate (PGMEA) or propylene glycol monomethyl ether (PGME),
an aromatic hydrocarbon-based solvent such as toluene, and a hydrocarbon-based solvent
such as hexane.
[0059] The surfactant of the present embodiment contains the fluorinated imide salt compound
described above. Therefore, the surfactant has a high surface tension-reducing ability.
Furthermore, the surfactant of the embodiment has high solubility in an aqueous solvent
or an organic solvent. Therefore the surfactant can be used for various uses.
[0060] The embodiments of the present invention have been described so far. However, the
present invention is not limited thereto, and can be appropriately changed within
the technical scope of the present invention, which is as defined in the appended
claims.
EXAMPLES
[0061] Hereinafter, the effects of the present invention will be described with reference
to examples. In the present examples, products were identified by
19F-NMR.
[Example 1 of the present invention]
[0062] A mixture (286.9 g) of CF
3SO
2NHK and KF and 425 mL of acetonitrile were put into a 4-neck glass flask equipped
with a reflux condenser, a thermometer, and a stirrer, and stirred so that CF
3SO
2NHK was dissolved, thereby preparing a mixed solution containing dispersed KF. The
mixture of CF
3SO
2NHK and KF was synthesized with reference to the method described in paragraph "0067"
of
Japanese Patent No. 5730513 by using trifluoromethanesulfonyl fluoride (CF
3SO
2F) instead of heptafluoropropanesulfonyl fluoride (C
3F
7SO
2F).
[0063] Then, while being stirred, the prepared mixed solution was cooled with ice water,
and 345.7 g of CF
3CF
2CF
2OCF(CF
3)CF
2OCF(CF
3)COF (CHEMINOX PO-3-AF, Unimatec Corporation.) was added dropwise to the mixed solution
for 15 minutes. After the dropping ended, the ice water was removed, and the mixed
solution was stirred at room temperature for 1 hour. Thereafter, the reaction solution
was filtered, KF•HF precipitated during the reaction was separated by filtration,
and the obtained filtrate was concentrated using an evaporator. Ethyl acetate (180
mL) was added to the concentrated solution, and then the solution was rinsed with
water 3 times. The ethyl acetate solution rinsed with water was concentrated using
an evaporator, thereby obtaining a fluorinated imide potassium salt compound (369.3
g, yield: 80%) represented by Formula (12).

[0064] 19F-NMR (CD
3OD): δ -78.8 (CF
3, 3F), -79.4 (CF, 1F), -79.8 (CF
3, 3F), -80.9 (CF
3 + CF
2, 5F), -81.7 (CF
3, 3F), -82.0 (CF, 1F), -128.5 (CF, 1F), -129.3 (CF
2, 2F), - 144.4 (CF, 1F)
[Example 2 of the present invention]
[0065] A fluorinated imide potassium salt compound (yield: 71%) represented by Formula (13)
was obtained in the same manner as in Example 1 of the present invention, except that
a mixture of CF
3CF
2CF
2CF
2SO
2NHK and KF was used instead of the mixture of CF
3SO
2NHK and KF.
[0066] The mixture of CF
3CF
2CF
2CF
2SO
2NHK and KF was synthesized with reference to the method described in paragraph "0067"
of
Japanese Patent No. 5730513 by using nonafluorobutanesulfonyl fluoride (CF
3CF
2CF
2CF
2SO
2F) instead of heptafluoropropanesulfonyl fluoride (C
3F
7SO
2F).

[0067] 19F-NMR (CD
3OD): δ -79.3 (CF, 1F), -79.9 (CF
3, 3F), -80.9 (CF
3, 3F), -81.2 (CF
3 + CF
2, 5F), -81.6 (CF
3, 3F), -82.0 (CF, 1F), -113.6 (CF2, 2F), -120.5 (CF2, 2F), - 125.6 (CF2, 2F), -128.4
(CF, 1F), -129.3 (CF
2, 2F), -144.3 (CF, 1F)
[Example 3 of the present invention]
[0068] A fluorinated imide potassium salt compound (yield: 73%) represented by Formula (14)
was obtained in the same manner as in Example 1 of the present invention, except that
CF
3CF
2CF
2OCF(CF
3)CF
2OCF(CF
3)CF
2OCF(CF
3)COF (manufactured by SynQuest Laboratories) was used instead of CF
3CF
2CF
2OCF(CF
3)CF
2OCF(CF
3)COF.

[0069] 19F-NMR (CD
3OD): -78.6 to -82.6 (CF
2 + CF
2 + CF
2, 6F), -78.8 (CF
3, 3F), -79.7 (CF
3 + CF
3, 6F), -81.2 (CF
3, 3F), -81.6 (CF
3, 3F), -128.4 (CF, 1F), -129.3 (CF
2, 2F), - 144.4 (CF + CF, 2F)
[Example 4 of the present invention]
[0070] The fluorinated imide potassium salt compound (300.0 g) obtained in Example 1 of
the present invention and 276.3 g of concentrated sulfuric acid were put into a 4-neck
glass flask equipped with a reflux condenser, a thermometer, and a stirrer, and distilled
under reduced pressure while being stirred, thereby obtaining a fluorinated imide
compound A represented by Formula (15) (141.4 g, yield: 50%, boiling point: 107°C
to 113 °C/2700 Pa (20 Torr))

[0071] Then, 943.3 g of ultrapure water and 11.6 g of aqueous ammonia having a concentration
of 25% were put into a polyethylene container having a volume of 2 L equipped with
a stirrer, and 103.0 g of the fluorinated imide compound A was added dropwise through
a dropping funnel to the container while being stirred so that the solution was neutralized.
The obtained aqueous solution was dried in a dryer at 120°C, thereby obtaining a fluorinated
imide ammonium salt compound represented by Formula (16) (104.7 g, yield: 99%).

[0072] 19F-NMR (CD
3CN): δ-78.4 (CF
3, 3F), -79.5 (CF
3 + CF, 4F), -80.7 (CF
3 + CF
2, 5F),-81.3 (CF
3, 3F), -81.9 (CF, 1F), -127.9 (CF, 1F), -128.9 (CF
2, 2F), -144.3 (CF, 1F)
[Example 5 of the present invention]
[0073] A fluorinated imide compound B represented by Formula (17) (yield: 45%, boiling point
102°C to 103 °C/270 to 400 Pa (2 to 3 Torr)) was obtained in the same manner as in
Example 4 of the present invention, except that the fluorinated imide potassium salt
compound obtained in Example 2 of the present invention was used instead of the fluorinated
imide potassium salt compound obtained in Example 1 of the present invention.

[0074] Then, a fluorinated imide ammonium salt compound (yield: 99%) represented by Formula
(18) was obtained in the same manner as in Example 4 of the present invention, except
that the fluorinated imide compound B was used instead of the fluorinated imide compound
A.

[0075] 19F-NMR (CD
3CN): δ -79.5 (CF, 1F), - 79.5 (CF
3, 3F), -80.4 (CF
3, 3F), -80.8 (CF
3 + CF
2, 5F), -81.3 (CF
3, 3F), -81.5 (CF, 1F), -113.6 (CF2, 2F), -120.6 (CF2, 2F), - 125.3 (CF2, 2F), -127.8
(CF, 1F), -128.9 (CF
2, 2F), -144.3 (CF, 1F)
[Example 6 of the present invention]
[0076] A fluorinated imide triethylammonium salt compound (yield: 99%) represented by Formula
(19) was obtained in the same manner as in Example 4 of the present invention, except
that triethylamine was used instead of the aqueous ammonia having a concentration
of 25%.

[0077] 19F-NMR (CD
3CN): δ-78.7 (CF
3, 3F), -79.6 (CF
3 + CF, 4F), -80.9 (CF
3 + CF
2, 5F),-81.4 (CF
3, 3F), -81.8 (CF, 1F), -127.8 (CF, 1F), -129.0 (CF
2, 2F), -144.4 (CF, 1F)
[Example 7 of the present invention]
[0078] A fluorinated imide tetramethylammonium salt compound (yield: 99%) represented by
Formula (20) was obtained in the same manner as in Example 4 of the present invention,
except that tetramethylammonium hydroxide (10% aqueous solution) was used instead
of the aqueous ammonia having a concentration of 25%.

[0079] 19F-NMR (CD
3CN): δ-78.7 (CF
3, 3F), -79.6 (CF
3 + CF, 4F), -80.9 (CF
3 + CF
2, 5F),-81.4 (CF
3, 3F), -81.8 (CF, 1F), -127.8 (CF, 1F), -129.0 (CF
2, 2F), -144.4 (CF, 1F)
[Comparative Example 1]
[0080] A commercially available bis(perfluorobutanesulfonyl)imide potassium salt: (C
4F
9SO
2)
2N
-K
+ (manufactured by TOKYO CHEMICAL INDUSTRY CO., LTD.) was prepared.
[Comparative Example 2]
[0081] A commercially available potassium salt of perfluorooctanesulfonic acid (PFOS) (manufactured
by TOKYO CHEMICAL INDUSTRY CO., LTD.) was prepared.
[Comparative Example 3]
[0082] A fluorinated imide potassium salt compound (yield: 73%) represented by Formula (21)
was obtained in the same manner as in Example 1 of the present invention, except that
CF
3CF
2CF
2OCF(CF
3)COF (CHEMINOX PO-2-AF, Unimatec Corporation.) was used instead of CF
3CF
2CF
2OCF(CF
3)CF
2OCF(CF
3)COF.

[Comparative Example 4]
[0083] A fluorinated imide potassium salt compound (yield: 71%) represented by Formula (22)
was obtained in the same manner as in Example 1 of the present invention, except that
a mixture of CF
3CF
2SO
2NHK and KF was used instead of the mixture of CF
3SO
2NHK and KF and that CF
3CF
2CF
2OCF(CF
3)COF (CHEMINOX PO-2-AF, Unimatec Corporation.) was used instead of CF
3CF
2CF
2OCF(CF
3)CF
2OCF(CF
3)COF.
[0084] The mixture of CF
3CF
2SO
2NHK and KF was synthesized with reference to the method described in paragraph "0067"
of
Japanese Patent No. 5730513 by using pentafluoroethanesulfonyl fluoride (CF
3CF
2SO
2F) instead of heptafluoropropanesulfonyl fluoride (C
3F
7SO
2F).

[Comparative Example 5]
[0085] The fluorinated imide compound A obtained in Example 4 of the present invention was
used.
[Evaluation]
[0086] The surface activity of the compounds obtained in Examples 1 to 7 of the present
invention and Comparative Examples 1 to 5 and the stability of the compounds in water
were evaluated.
(Surface activity)
[0087] Each of the compounds was mixed with water so that an aqueous solution having a concentration
of 1,000 ppm by mass was prepared. By measuring the surface tension of the prepared
aqueous solution, the surface activity was evaluated. The surface tension was measured
by the Wilhelmy method using an automatic surface tensiometer CBVP-Z manufactured
by Kyowa Interface Science Co., LTD. The measurement results are shown in the following
Table 1. The potassium salt of PFOS of Comparative Example 2 formed a saturated aqueous
solution without being completely dissolved in water. Therefore, in Comparative Example
2, the surface tension was measured in the saturated state.
(Stability in water)
[0088] Each of the compounds was mixed with water so that an aqueous solution having a concentration
of 10% by mass was prepared. The prepared aqueous solution was stored for 20 days
in a room adjusted to 20°C to 25°C. By calculating a decomposition rate of the compound
from
19F-NMR spectra of the compound in the aqueous solution that were obtained before and
after the storage, the stability in water was evaluated. The decomposition rate was
calculated by the following formula. A compound having a decomposition rate of 3%
or less was described as "No decomposition". The measurement results are shown in
the following Table 1. The potassium salt of PFOS of Comparative Example 2 formed
a saturated aqueous solution without being completely dissolved in water. Therefore,
in Comparative Example 2, the stability in water was evaluated in the saturated state.
[Table 1]
|
Surface tension (mN/m) |
Stability in water |
Example 1 of the present invention |
24 |
No decomposition |
Example 2 of the present invention |
17 |
No decomposition |
Example 3 of the present invention |
16 |
No decomposition |
Example 4 of the present invention |
24 |
No decomposition |
Example 5 of the present invention |
18 |
No decomposition |
Example 6 of the present invention |
24 |
No decomposition |
Example 7 of the present invention |
23 |
No decomposition |
Comparative Example 1 |
43 |
No decomposition |
Comparative Example 2 |
41 (saturated) |
No decomposition |
Comparative Example 3 |
55 |
No decomposition |
Comparative Example 4 |
50 |
No decomposition |
Comparative Example 5 |
18 |
30% decomposition |
[0089] It has been revealed that the fluorinated imide salt compounds of Examples 1 to 7
of the present invention have a higher surface tension-reducing ability, compared
to the conventional fluorinated compounds, such as bis(perfluorobutanesulfonyl)imide
potassium salt of Comparative Example 1 and perfluorooctanesulfonic acid (PFOS) of
Comparative Example 2, and the fluorinated imide salt compounds of Comparative Examples
3 and 4 in which oxyperfluoropropyl group is bonded to a carboxylic acid group of
imide without the intervention of an oxyperfluoropropylene group.
[0090] Furthermore, it has been revealed that the fluorinated imide salt compounds of Examples
1 to 7 of the present invention are more stable in water, compared to the fluorinated
imide compound of Comparative Example 5 which does not have a salt structure.